Balancing Equations
1) Balance the following equation:
B2O3(s) + HF(l) → BF3(g) + H2O(l)
A. because on the left side you have 3 O and you need to give the right side 3 oxygen as well so put a 3 in front of H2O, which makes 6 H on the right so you put a 6 in front of the HF so you have 6 F on the left, so you put a 2 in front of BF3 so you have 6 F and 2 B, which makes the equation balanced.

A. B2O3(s) + 6HF(l) → 2BF3(g) + 3H2O(l)
B. B2O3(s) + H6F6(l) → B2F6(g) + H6O3(l)
C. B2O3(s) + 2HF(l) → 2BF3(g) + H2O(l)
D. B2O3(s) + 3HF(l) → 2BF3(g) + 3H2O(l)
E. B2O3(s) + 6HF(l) → 2BF3(g) + 6H2O(l)
2) Balance the following equation:




UO2(s) + HF(l) → UF4(s) + H2O(l)
A. UO2(s) + 2HF(l) → UF4(s) + H2O(l)
B. UO2(s) + 4HF(l) → UF4(s) + 2H2O(l)
C. UO2 (s) + H4F4(l) → UF4 (s) + H4O2(l)
D. UO2(s) + 4HF(l) → UF4(s) + 4H2O(l)
E. UO2(s) + 8HF(l) → 2UF4(s) + 4H2O(l)
3) Balance the following equation for the combustion of benzene:C




C6H6(l) + O2(g) → H2O(g) + CO2(g)
A. C6H6(l) + 9O2(g) → 3H2O(g) + 6CO2(g)
B. C6H6(l) + 9O2(g) → 6H2O(g) + 6CO2(g)
C. 2C6H6(l) + 15O2(g) → 6H2O(g) + 12CO2(g)
D. C6H6(l) + 15O2(g) → 3H2O(g) + 6CO2(g)
E. 2C6H6(l) + 9O2(g) → 6H2O(g) + 12CO2(g)
4) Balance the following equation: B because there are 18 H on the left so you put a 9 in front of the H2O then you put a 8 in front of the CO2 so you have 8 C on each side then you need to put an 11 in front of the O2 so you have 25 O on each side.
C8H18O3(l) + O2(g) → H2O(g) + CO2(g)
A. C8H18O3(l) + 8O2(g) → 9H2O(g) + 8CO2(g)
B. C8H18O3(l) + 11O2(g) → 9H2O(g) + 8CO2(g)
C. 2C8H18O3(l) + 22O2(g) → 9H2O(g) + 16CO2(g)
D. C8H18O3(l) + 13O2(g) → 18H2O(g) + 8CO2(g)
E. 2C8H18O3(l) + 17O2(g) → 18H2O(g) + 16CO2(g)
5) Balance the following equation: D because you have 4P on th right then you put a 2 in front of the Ca2(PO4)2 which makes 6 Ca on the left so you then put a 6 in front of the CaSiO3 so you put a 6 in front of the SiO2 so then you have 28 O on the left so you put a 10 in front of Co then you put a 10 in front ofthe C on the left.
Ca3(PO4)2(s) + SiO2(s) + C(s) → CaSiO3(s) + CO(g) + P4(s)
A. Ca3(PO4)2(s) + 3SiO2(s) + 8C(s) → 3CaSiO3(s) + 8CO(g) + P4(s)
B. Ca3(PO4)2(s) + 3SiO2(s) + 14C(s) → 3CaSiO3(s) + 14CO(g) + P4(s)
C. Ca3(PO4)2(s) + 3SiO2(s) + 8C(s) → 3CaSiO3(s) + 8CO(g) + 2P4(s)
D. 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) → 6CaSiO3(s) + 10CO(g) + P4(s)
E. 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) → 6CaSiO3(s) + 10CO(g) + 4P4(s)
6) Select the precipitate that forms when the following reactants are mixed.
Na2CO3(aq) + BaCl2(aq) → C 2NaC, you find what the reactin produces which is NaCl + BaCO3 then you baance the equation and use the blue chart to find which of the products is the solid, that is the precipitate, but mrs wilson says it is B
A. Ba2CO3
B. BaCO3
C. 2NaCl
D. NaCl2
E. BaO
7) Select the precipitate that forms when the following reactants are mixed.
Mg(C2H3O2)2(aq) + LiOH(aq) → A you find the products of the reactants then you balance the equation and you find which of the products are solid using the blue chart, but mrs wilson says it is D
A. 2LiC2H3O2
B. Li(C2H3O2)2
C. MgOH
D. Mg(OH)2
E. CH3OH
8) Select the precipitate that forms when aqueous ammonium sulfide reacts with aqueous copper(II) nitrate. C you find the products of the reactants then you balance the equation and you find which of the products are solid using the blue chart but mrs wilson says it is A
A. CuS
B. Cu2S
C. 2NH4NO3
D. NH4(NO3)2
E. CuSO4
9) Select the precipitate that forms when aqueous lead(II) nitrate reacts with aqueous sodium sulfate. A you find the products of the reactants then you balance the equation and you find which of the products are solid using the blue chart, but mrs wilson says it is C
A. 2NaNO3
B. Na2NO3
C. PbSO4
D. Pb2SO4
E. PbS
10) Select the correct name and chemical formula for the precipitate that forms when the following reactants are mixed. E because NaCl is the only precipitant that forms from this equation, but Mrs wilson says it is D
CuCl2(aq) + Na2CO3(aq) →
A. copper(I) carbonate, Cu2CO3
B. copper(II) carbonate, Cu2CO3
C. copper(I) carbonate, CuCO3
D. copper(II) carbonate, CuCO3
E. sodium chloride, NaCl
11) Select the correct name and chemical formula for the precipitate that forms when the following reactants are mixed. E because NaCl is the only precipitant that forms from this equation, but mrs wilson says it is A
CoSO4(aq) + (NH4)3PO4(aq) →
A. cobalt(II) phosphate, Co3(PO4)2
B. cobalt(III) phosphate, Co3(PO4)2
C. cobalt(II) phosphate, CoPO4
D. cobalt(III) phosphate, CoPO4
E. ammonium sulfate, (NH4)2SO4
12) The compound P4O10 is used in refining sugar. Select the classification for the reaction in which it is synthesized. A because there are 2 substances combning to form one
P4(s) + 5O2(g) → P4O10(s)
A. combination
B. decomposition
C. displacement
D. acid-base
E. precipitation
13) Select the classification for the following reaction.
H2CO3(aq) → H2O(l) + CO2(g) B because it has CO2 in it
A. combination
B. decomposition
C. displacement
D. acid-base
E. none of these choices is correct
14)Predict the product(s) for the following reaction. A becaus when you find the charges of the substances these are the ones that match up
H2SO4(aq) + KOH(aq) →
A. K2SO4(aq) + H2O(l)
B. K2S(aq) + H2O(l)
C. K(s) + H2(g) + SO3(g)
D. KSO4(aq) + H2O(l)
E. No reaction occurs.
15) Predict the product(s) for the following reaction. B becaus when you find the charges of the substances these are the ones that match up
MgCO3(s)
A. MgO2(s) + CO(g)
B. MgO(s) + CO2
C. Mg(s) + CO2(g) + O2(g)
D. Mg2+(s) + CO2(g) + O2(g)
E. No reaction occurs.